Spring assembly



Oct. 3, 1961 J. VAN HULST SPRING ASSEMBLY Filed May 25, 1959 vmwn ww, H W N. I

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United rates Patent 3,002,740 SPRING ASSEMBLY Jan van Hulst, Amersfoort, Netherlands, assignor to N.V. Outwikkelingmaatschappij Multinorm, Amersfoort, Netherlands, a Dutch limited liability company Filed May 25, 1959, Ser. No. 815,549 Claims priority, application Netherlands May 23, 1958 4 Claims. (Cl. 267--1) This invention relates to Spring assemblies comprising a plurality of convexo-concave resilient spring elements, top and bottom press plate members and elements engaging at least one of the said press plate members for holding the parts in assembled relation.

It is the general object of my invention to provide a simple and improved spring assembly of this kind so designed that it may be readily manufactured and easily assembled within a proportionally essentially restricted space.

A still further object of the invention is the provision of such a spring assembly which is extremely efiicient in operation and when compressed combines both a high spring compression strength and an elevated output power.

Another object of the invention is the manufacture of a new and improved spring element for use in a spring assembly of which the rate of filling is equal to 1.

My invention further relates to arrangements and cornbinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

For a better understanding of the invention, reference is made to the accompanying drawings, in which FIG. 1 is a horizontal cross section taken along line II of FIG. 2 and showing a spring assembly constructed in accordance with one embodiment of this invention;

FIG. 2 is a cross section along line -II'II of FIG. 1;

FIG. 3 is a cross section along line IIIIII of FIG. 1;

FIG. 4 is a detail view which illustrates on a larger scale the area of contact of two spring elements engaging each other and having their concave sides facing toward each other in the spring assembly of FIGS. 1, 2 and 3;

FIG. 5 is a cross section of a group of four spring elements in another embodiment of the invention;

FIG. 6 is an elevational view of a spring assembly constructed in accordance with another embodiment of this invention;

FIG, 7 is a cross section along line VLF-VII of FIG. 6;

FIG. 8 is an elevational view of a spring assembly constructed in accordance with still another embodiment of this invention; and

FIG. 9 is a cross section along line IX-IX of FIG. 7.

Referring to FIGURES l to 3, inclusive, my improved spring assembly comprises a stack of six spring elements 1 each constructed of a rhombic plate of spring metal and formed in the shape of a concavo-convex spring element by bending said rhombic-plate symmetrically about one of its two diagonals out of the horizontal plane, While that one diagonal of the rhombic plate remains undisturbed and of an unchanged length. Thus the extremities of the diagonal about which the rhombic plate is bent form guiding points 2 and 3 engaging the slots 4 and 5, respectively, arranged in posts 6 and 7, respectively, of a closed shaft frame. Thus the stack of spring elements 1 assembled in my spring assembly are guided laterally solely by means of said guiding points 2 and 3 in said shaft frame. It is appreciated that during the flexing of the spring elements the diagonal about which each of them is bent remains stretched at all times never changing its length independent of the rate of bending of the re lated spring element, even when said element is compressed so far as to extend in a flat plane. In this manner the guiding will be accurate to a large extent, but it is desired that the angle between the sides of the slots 4 and 5 be slightly greater than the divergence of the side edges of the spring element when the latter is compressed completely and extends again in a flat plane. All of the six spring elements are piled up in pairs with the elements in each pair having their concave sides facing toward each other, as shown in FIG. 2. Thus the spring elements of each pair engage each other only at the corners thereof formed at the extremities of their related diagonals which are bent when manufacturing the spring elements. However, to prevent the spring elements from shifting laterally with respect to each other as soon as there is a slight moving in my spring assembly the surfaces of the spring elements of each pair are rounded at the places of contact as shown in FIG. 4 ensuring in this manner at the same time that the elements roll against. each other in an undisturbed movement when the spring elements are compressed or released in my spring assembly.

The spring elements 1 are held between an upper support plate 8 and a bottom plate 9 of the closed shaft frame, said upper support plate slidably engaging the posts 6 and 7 which are fixed to the bottom plate 9. Applying a pressure to the top side of the upper support plate causes the latter to yield and to be forced in the direction toward the bottom plate, thereby compressing the spring assembly.

It is appreciated that there are a plurality of ways in which the spring elements can be stacked in my spring assembly. Possibly all of the Spring elements may be arranged with their concave sides facing in only one direction. Further, in the embodiment as shown particularly in FIG. 5 there are four spring elements arranged in pairs, with the elements of each pair having their concave sides contacting each other over the full area thereof, however, both pairs form a set in which the concave sides face towards each other. A much preferred shape of the spring element is obtained by bending the plate of spring metal symmetrically like a section of a cylinder. Further any suitable resilient material may be used for the manufacture of the spring elements, however, it is preferred to use plate metals which permits reduction of the thickness of the spring element as far as possible increasing in this way the bending stress in a remarkable way. Finally it is preferable, though not necessary to impose an initial compression on the spring elements when assembling the elements in a spring assembly.

Referring to the FIGURES 6 to 9, inclusive, there are shown by way of example spring assemblies of the invention in which the spring elements 10 are arranged in two groups. In this case each of the elements 10 preferably has a square shape. In each of the groups respectively arranged in the top and the bottom parts of the spring assembly, respectively, all of the bending diagonals of the several spring elements extend in the same direction, while all of the bending diagonals of one group are at an angle of with respect to all of the bending diagonals in the other group.

Both the groups may be arranged within a compression box as is illustrated especially in FIGURES 6 and 7.

The compression box includes upper and lower parts which are vertically movable relative to each other. The upper part includes a top wall and right angled wall portions 11 and 11a depending from the top wall along diagonally opposed corner edge portions of the latter, and the lower part includes a bottom wall and right angled wall portions 12 and 12a extending upwardly from diagonally opposed corner edge portions of the bottom wall. Each of the right angled wall portions 11, 11a, 12 and 12a has a height equal to the uncompressed height of one of the groups of the spring elements 10, and extends transversely along one-quarter of the periphery of the latter. Thus the right angled walls 11 and 11a of the upper movable part of the box define corners guiding the points of all of the spring elements belonging to the upper group of the spring assembly. It is appreciated that necessarily the diagonal of the horizontal cross section of the square compression box has to be exactly equal to the diagonal of the square spring units it In the lower part of the compression box, the right angled walls 12 and 12a form the guide ways for all of the spring ele ments arranged in the lower group of the spring assembly. The four right angled walls 11, 11a, 12, and 12a, respectively, are dimensioned so that when the box is compressed vertically, the parts of the box slide into each other with the wall portions 12 and 12a fitting into the spaces between the wall portions 11 and 11a. To ensure the assembling of all of the parts there is arranged a rigid square flat plate 13 halfway up within the box, with the plate 13 engaging exactly all of the wall parts which, when moving up and down, slide about said rigid plate 13. Moreover, said rigid plate 13 forms a support for the upper group of the spring elements, and at the same time a stop for the lower group of spring elements. The effect of this arrangement is to obtain a maximal economy of space, because the compression box itself will have its vertical dimension reduced when a pressure is applied thereto.

The same effect may be obtained by using a telescopic post frame as shown particularly in FIGURES 8 and 9 which consists of two separate post frames arranged crosswise with the posts of the two of them extending only along a portion of the total height of the complete spring assembly. All of the spring elements in the lower group of the spring assembly are guided by slots provided in the opposite posts 14 and 14a fixed to a bottom member 17 The guiding points of all of the spring elements in the upper group are engaging the slots arranged in the posts 15 and 15a, respectively, suspended from the upper plate 18 of said compression shaft frame, with the axes of the posts 15 and 15a lying in a plane at right angles to the plane containing the axes of the posts 14 and 14a. It is to be appreciated that the guide ways inside the slots of the four posts of said compression shaft frame form the Corners of a square exactly equal to the square planform of each of the spring elements of the related spring assembly when the spring element is compressed completely into a flat plane. To ensure the assembling of all parts in this embodiment there is arranged a rigid square fiat separating plate 16 between both of the groups of spring units of the spring assembly, said separating plate engaging at its four corners in the slots of the posts 14, 14a, 15 and 15a, respectively.

What is claimed is:

1. A spring assembly comprising a plurality of identical spring elements each in the form of an equilateral parallelogram which is bent symmetrically out of a flat plane about only one of the diagonals thereof so as to be concave at one side and convex at the other side with said one diagonal remaining straight, said spring elements being arranged in pairs with the concave sides of the spring elements facing each other in each of said pairs so that the spring elements of each pair engage each other only at the corners thereof disposed at the ends of the other diagonal of each spring element, and frame means for holding said spring elements in assembled relationship including means defining guideways slidably receiving only the corners of each of said spring elements disposed at the ends of said one diagonal which remains straight, each of said guideways having converging surfaces including an angle that is slightly larged than the angle included in the corner of each spring element slidably received therein.

2. A spring assembly comprising a stack of identical spring elements each in the form of an equilateral parallelogram which is bent symmetrically out of a flat plate about only one of the diagonals thereof which remains straight so that each spring element has a concave side and a convex side, said spring elements being arranged in first and second groups with said one diagonals of all of the spring elements in said first group extending inone direction and with said one diagonals of all of the spring elements in said second group extending in another direction which is angularly displaced with respect to said one direction, the spring elements in each of said groups being arranged in pairs with the spring elements of each pair having the concave sides thereof facing each other so that said spring elements of each pair are in contact only at the corners thereof at the ends of the other diagonal of each spring element, and frame means for holding the spring elements in assembled relationship including a rigid plate between said groups of spring elements, and first and second relatively movable parts accommodating said first and second groups, respectively, each of said parts including an end member and guide defining means extending from said end member and slidably receiving only those corners of the spring elements of the related group at the ends of said one diagonal of each spring element, the guide defining means of said first and second parts having lengths which are substantially equal to the uncompressed heights of the related groups of spring ele ments and being interfitted so that the guide defining means of said first part can slide between the guide defining means of said second part upon compression of said stack of spring elements.

3. A spring assembly as in claim 2; wherein each of said spring elements is formed of a resilient plate having a square planform when pressed into a fiat plane, and said one diagonals of the spring elements in said first group extend at right angles to said one diagonals of the spring elements in said second group; and wherein said end member of each of the relatively movable parts of the frame means is in the form of a square plate and said guide defining means includes right angle wall portions extending from diagonally opposed corner edge portions of said square plate, each of said right angle wall portionshaving a cross-sectional extent equal to one-fourth the length of the periphery of said square plate.

4. A spring assembly as in claim 2; wherein each of said spring elements is formed of a resilient plate having a square planform when pressed into a flat plane, and said one diagonals of the spring elements in said first group extend at right angles to said one diagonals of the spring elements in said second group; and wherein said guide defining means of each of said relatively movable parts includes two parallel posts having longitudinal grooves opening toward each other and each having right angularly related side surfaces, said side surfaces of the grooves in the posts of the first and second parts defining the corners of a square which is equal to said square planform of the resilient plate forming each spring element.

References Cited in the file of this patent UNITED STATES PATENTS Re. 2,314 Allyn July 17, 1866 119,129 Elliot Sept. 19, 1871 231,019 Davis Aug. 10, 1880 1,139,732 Slick May 18, 1915 1,818,362 Symington Aug. 11, 1931 2,708,110 Clay May 10, 1955 

